1. Field of the Invention
The present invention relates to a transformer and a switched-mode power supply apparatus using the same, particularly a configuration of the transformer.
2. Background of the Invention
In order to operate an electrical device or electrical circuit, stable DC voltage is required and a switched-mode power supply apparatus has been conventionally used for this purpose. The switched-mode power supply apparatus rectifies and smooths a voltage which is supplied by an external power source; performs switching operation due to a semiconductor switching element to input the voltage into a primary winding of the transformer; and supplies DC voltage from a secondary winding to a load through a smoothing operation performed by a smoothing circuit. Furthermore, an output voltage is monitored, and the time ratio of the semiconductor switching element is adjusted by a control circuit so that the output voltage is constantly maintained.
As the switched-mode power supply apparatus, multi-output switched-mode power supply apparatus has been conventionally known. A transformer for the above multi-output switched-mode power supply apparatus has a core, a primary winding which is provided in a core, and at least two secondary windings which are also provided in the core.